Regioselectivity of Diels-Alder reactions of a surfactant 1,3-diene with surfactant dienophiles
摘要:
The ability of aqueous surfactant aggregates to control the regiochemistry of Diels-Alder reactions was investigated with surfactant 1,3-diene 4-[p-[[3-[(p-octylphenyl)thio]-1,3-butadien-2-yl]thio]phenyl]-N,N,N-trimethyl-1-butanaminium bromide (6), derived in situ by thermal extrusion of SO2 from 4-[[[1,1-dioxo-4-[(p-octylphenyl)thio]-2,5-dihydrothiophen-3-yl]thio]phenyl]-N,N,N-trimethyl-1-butanaminium bromide (8), and surfactant dienophiles (E)-6-[[[2-(alkoxycarbonyl)ethenyl]carbonyl]-oxy]-N,N,N-trimethyl-1-hexanaminium bromide (7) (a, R = Me; b, R = Bu; c, R = C8H17). In each case an excess of 1-[[p-[(4-trimethylammonio)butyl]phenyl]thio]-2-[(p-octylphenyl)thio]-4-(alkoxycarbonyl)-5-[[6-(trimethylammonio)hexoxy]carbonyl]-1-cyc lohexene dibromide (16) over 1-[[p-[(4-trimethylammonio)butyl]phenyl]thio]-2-[(p-octylphenyl)thio]-4-[[6-(trimethylammonio)hexoxy]carbonyl]-5-(alkoxycarbonyl)-1-cyc lohexene dibromide (17) was obtained, consistent with the reaction of 6 and 7 within a mixed aggregate in their preferred orientations at the aggregate-H2O interface. The cyclohexene rings of 16 and 17 have different conformational character in chloroform resulting from supramolecular effects within reversed micelles.
Intramolecular cycloadditions with azomethine ylides for the synthesis of metacyclophanes
作者:W. Eberbach、H. Fritz、I. Heinze、P. von Laer、P. Link
DOI:10.1016/s0040-4039(00)84895-9
日期:1986.1
On thermal treatment of the aziridines - intramolecularcycloaddition reactions of the intermediate azomethine ylides result in the formation of the metacyclophanes - . For and the conformational barriers areestimated to be approximately 20 and 12 kcal/mol, respectively.